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Discover how PEPperPRINT Peptide Microarray products have been used in different fields of research.

Development of a novel histidine-rich glycoprotein measurement system as a biomarker for sepsis

Uchiumi, Takaoki; Nishibori, Masahiro; Morimatsu, Hiroshi; Inoue, Yoko; Nishi, Hiroshi; Ota, Norio
Journal of Immunological Methods.
May 2025
The plasma histidine-rich glycoprotein concentration is a marker of sepsis severity. In this study, we generated selective and specific monoclonal antibodies against histidine-rich glycoprotein for use in a prototype enzyme-linked immunosorbent assay-based in vitro diagnostic system. First, we investigated the properties of monoclonal antibodies produced by 21 hybridomas that we developed using immunized mice, and we identified monoclonal antibodies 69-1A and 75-2D to be the most suitable combination for use in the sandwich enzyme-linked immunosorbent assay. Wild-type histidine-rich glycoprotein (Form-1, 75 kDa) with a proline residue at amino acid position 204 is the most common isoform of the protein in humans, followed by its variant (Form-2, 77 kDa), which has a serine residue at position 204. The epitope mapping was examined for the HRG amino acid sequence with 69-1A and 75-2D mAbs to achieve the identification of respective specific binding domains, though the other kinds of mAbs showed considerably complex domains. The identified epitopes recognized by 69-1A and 75-2D monoclonal antibodies did not span position 204. Furthermore, immunoprecipitation-immunoblotting analysis showed that the 69-1A and 75-2D monoclonal antibodies could bind to both Form-1 and Form-2 in human plasma samples. Thus, these two new antibodies can be used to clearly detect both forms of histidine-rich glycoproteins in human plasma samples. In our analysis of clinical samples by enzyme-linked immunosorbent assays using various combinations of our newly synthesized antibodies, we found that the histidine-rich glycoprotein concentration was significantly lower in plasma samples from septic patients than in those from healthy volunteers (p < 0.01). Thus, our novel analysis system using the new antibodies is expected to be a useful tool for sepsis research, and it may be adapted as an in vitro diagnostic tool for many other kinds of diseases in the future.

Preclinical characterization of an active immunotherapy targeting calcitonin gene-related peptide

Boyd, Justin D.; Wang, Shixia; Lin, Hsiao-Wen; Hsieh, Yueh-Ting; Sun, Yu Shuang; Thibodeaux, Brett A.; Lu, Hanxin; Sahni, Jaya; Wiggins, Jonathan; Longo, Matthew S.; Brooks, Jeanne K.; Vroom, Madeline M.; Chang, Yi-Pin; Liu, Zhi; Ding, Shuang; Dodart, Jean-Cosme
Commun Med.
Apr 2025
Abstract **Background** The success of passive immunotherapies targeting Calcitonin gene-related peptide (CGRP) for managing migraine has prompted our efforts towards developing an active immunotherapy that induces the production of endogenous antibodies against CGRP. Achieving efficacious antibody titers via immunization could provide a more convenient and cost-effective treatment alternative to anti-CGRP monoclonal antibody (mAb) therapies. However, immunization against endogenous CGRP faces multiple challenges such as breaking immune tolerance, inducing sufficient antibody titers, and avoiding immune response-associated toxicity. **Methods** Synthetic peptide immunogens formulated in adjuvants were delivered intramuscularly. Serum samples were collected post immunization and used to measure antibody titers as well as for the isolation of antibodies specific to CGRP. Antibodies were characterized for their binding affinities and specificities. The capsaicin-induced increase in dermal blood flow model was used in rats for the assessment of the pharmacodynamic effect of immunization. **Results** Here we demonstrate that a peptide-based active immunotherapy designed to induce antibodies against CGRP promotes robust antibody titers across preclinical species. Characterization of the immune response strongly suggests that this peptide immunogen primarily stimulates a humoral response and only induced CGRP-specific antibodies. Antibodies produced by immunization are primarily IgG1 and demonstrate binding and activity potencies similar to marketed monoclonal antibodies against CGRP. Finally, immunization demonstrates in vivo efficacy in a rat pharmacodynamic model. **Conclusion** Our results strongly suggest that a peptide-based active immunotherapy against CGRP could provide an affordable and convenient therapeutic for the prevention of migraine.

Paediatric autoimmune uveitis is associated with intraocular antibodies against Epstein–Barr virus Nuclear Antigen 1 (EBNA-1)

Hendrikse, Jytte; Bont, Louis J.; Schellekens, Peter A.W.J.F.; De Groot-Mijnes, Jolanda D.F.; De Boer, Joke H.; Kuiper, Jonas J.W.
eBioMedicine.
Mar 2025
**Background** Non-infectious uveitis is an immune-mediated disease characterized by vision-threatening inflammation within the eye. Increasing evidence indicates that microbial agents promote non-infectious uveitis, but the natural history of immune responses to pathogens in patients remains unexplored. We determined intraocular antibodies against pathogens in paediatric uveitis. **Methods** We used peptide microarrays containing 3760 linear B-cell epitopes from 196 human pathogens to profile IgG levels in eye fluid biopsies and paired serum samples from 18 Dutch paediatric patients and 6 age-matched controls. We compared intensities of single epitopes and clusters based on overlapping amino acid sequence of peptides. Next-generation sequencing data was obtained to determine the HLA-DRB1∗15:01 genotype. **Findings** Intraocular antibody profiles largely matched serum profiles and were characterized by high IgG against the conserved PALTAVET-motif of enterovirus family members, as well as broad epitope reactivity against Epstein–Barr virus (EBV). The aqueous humour of patients showed elevated levels of antibodies against peptides containing the RRPFFHPV-motif of Epstein–Barr Virus Nuclear Antigen 1 [EBNA-1]. Antibody levels against the RRPFFHPV-motif of EBNA1 were significantly higher in individuals that carry the HLA-DRB1∗15:01 risk allele of paediatric uveitis. **Interpretation** Intraocular antibodies against an immunogenic epitope of EBV showed an association with paediatric uveitis, particularly HLA-DRB1∗15:01 positive uveitis, indicating a potential link between EBV-specific immune responses and autoimmune uveitis. **Funding** Funding for this research was received from Fischer Stichting (UZ2022-3), ODAS (2021-02), LSBS and ANVVB.

Identification of Tripeptide Modulators of ACE2 Activity Using a High Throughput Screen (Abstract ID: 165381)

Walker, David F.; Karamyan, Vardan T.
The Journal of Pharmacology and Experimental Therapeutics.
Mar 2025
Angiotensin converting enzyme 2 (ACE2) works in the renin angiotensin aldosterone system to decrease circulating levels of angiotensin II by removing the C-terminal phenylalanine and converting it to angiotensin (1-7). In addition, ACE2 has received increased interest in research due to its role in COVID-19 pathogenesis, as the binding site and cell entry gate for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While ACE2 inhibitors have been primarily used as pharmacological tools to study the renin-angiotensin system, small molecule ACE2 enhancers (aka activators) are highly desired because of their hypothesized therapeutic potential. This study was designed to identify peptide-based enhancers of ACE2. First, binding of human recombinant ACE2 to all possible tripeptides composed of the 20 proteinogenic amino acids, was evaluated using a proprietary immunofluorescence-based peptide microarray. Binding of 6xHis-tagged ACE2 to the 8000 tripeptides immobilized on a microchip was evaluated at 10 µg/ml and 100 µg/ml concentrations of the peptidase using a DyLight680-conjugated anti-6xHis-tag antibody. Hemagglutinin (HA) immobilized on the microchip served as a positive control peptide in the microarray and it was tracked using a DyLight800-conjugated anti-HA antibody. The read-out was performed with an Innopsys InnoScan 710-IR Microarray Scanner at scanning gains of 50/10 (red/green). In the result of the microarray a number of tripeptides were identified as potential ACE2 binders. Among them, 22 tripeptides were selected to represent several the most pronounced binders as well as a number of structurally similar tripeptides that did not show appreciable binding to ACE2 to serve as negative control. The effect of the selected peptides (at 1, 10 and 100 µM) on activity of human recombinant ACE2 was tested in a continuous enzymatic assay using a fluorogenic substrate. Contrary to our expectation, none of the peptides affected the activity of ACE2 in a significant manner. These results suggest that the selected peptides do not alter activity of ACE2, but they do not exclude the possibility that some of the peptides may still bind to the peptidase. Our subsequent experiments will apply differential scanning fluorometry (DSF) to determine whether these peptides physically interact with recombinant ACE2.

A tumor-binding antibody with cross-reactivity to viral antigens

Campa, Michael J.; Gottlin, Elizabeth B.; Wiehe, Kevin; Patz, Edward F.
Cancer Immunol Immunother.
Feb 2025
**Background** We previously identified in non-small cell lung cancer (NSCLC) patients an autoantibody to complement factor H (CFH) that is associated with non-metastatic disease and longer time to progression in patients with stage I disease. A recombinant human antibody, GT103, was cloned from single B cells isolated from patients with the autoantibody. GT103 inhibits tumor growth and establishes an antitumor microenvironment. The anti-CFH autoantibody and GT103 recognize the epitope PIDNGDIT within the SCR19 domain of CFH. Here, we asked if this autoantibody could have originally arisen as a humoral response to a similar epitope in a viral protein from a prior infection. **Methods** Homologous viral peptides with high sequence identity to the core PIDNGDIT epitope sequence were identified and synthesized. NSCLC patient plasma containing anti-CFH autoantibodies were assayed by ELISA against these peptides. GT103 was assayed on a 4345-peptide pathogen microarray. **Results** Epitopes similar to the GT103 epitope are present in several viruses, including human metapneumovirus-1 (HMPV-1) that contains a sequence within attachment glycoprotein G that differs by one amino acid. Anti-CFH autoantibodies in NSCLC patient plasma weakly bound to an HMPV-1 peptide containing the epitope. GT103 cross-reacted with multiple viral epitopes on a peptide microarray, with the top hits being peptides in the human endogenous retrovirus-K polymerase (HERV-K pol) protein and measles hemagglutinin glycoprotein. GT103 bound the viral HMPV-1, HERV-K pol, and measles epitope peptides but with lower affinity compared to the GT103 epitope peptide. **Conclusion** These findings suggest that memory B cells against a viral target could have affinity matured to produce an antibody that recognizes a similar epitope on tumor cells and exhibits antitumor properties.

HCV immunodominant peptide mapping reveals unique HLA-A*02-restricted signatures: insights for CD8+ T-cell-based vaccines and immunotherapies

Cardoso Corrêa-Dias, Laura; Lopes-Ribeiro, Ágata; Marques-Ferreira, Geovane; Gomes-de-Pontes, Letícia; Pereira-Santos, Thaiza Aline; De Sousa Reis, Erik Vinicius; Silva Moraes, Thaís De Fátima; Assis Martins-Filho, Olindo; Figueiredo Barbosa-Stancioli, Edel; Guimarães Da Fonseca, Flávio; Coelho-dos-Reis, Jordana Grazziela
Immunogenetics.
Jan 2025
Several barriers for the development of an HCV vaccine still exist, including the genetic diversity of the virus, and the shortage of assessable models for in vitro and in vivo assays. Therefore, in this study, HCV epitope mapping was performed for 59 polyprotein sequences from 7 HCV genotypes. Around 2,880 peptides were considered epitopes for CD8+ T cells. The peptide induction of cytokines from Th1 and/or Th2 axes of the cellular immune response was assessed, indicating a tendency for Th2 axis. In vitro evaluation was performed using peptide microarray and a recombinant HLA-A*02:01 molecule. A total of 615 peptides of high reactivity to HLA-A*02:01 were identified, with predominance of leucine and tryptophan residues, highlighting their importance for TCR-epitope binding and CD8+ T activation. Finally, HCV-derived peptide patterns restricted to HLA-A2*02:01 observed in this study provide important information for the development of a multi-epitope-based pan-genotypic vaccine against the virus.

The antibody repertoire of autoimmune sensory neuronopathies targets pathways of the innate and adaptative immune system. An autoantigenomic approach.

Moritz, Christian P.; Tholance, Yannick; Boutahar, Nadia; Borowczyk, Coralie; Berger, Anne-Emmanuelle; Paul, Stéphane; Antoine, Jean-Christophe; Camdessanché, Jean-Philippe
Journal of Translational Autoimmunity.
Jan 2025
Sensory neuronopathies (SNN) encompasses diverse etiologies, with autoimmunity playing a major role through both cellular and humoral responses. To investigate the humoral autoantibody repertoire in autoimmune SNN, we conducted a retrospective cohort study using large Human Proteome-wide protein microarrays (HuProt 3.1, HuProt 4.0, ProtoArrays). We specifically focused on immune system pathways within the repertoire of targeted antigens (the autoantigenome). We included 131 participants: 44 patients with non-paraneoplastic autoimmune SNN (12 with anti-FGFR3 and/or anti-AGO antibodies), 8 with paraneoplastic SNN and 79 controls. Results were validated in an independent cohort of 16 SNN patients. Overrepresentation of immune-system-related proteins was assessed via the Reactome database, and serum levels of IFN-γ and IL-6 were measured using the Bio-Plex Pro™ Reagent Kit. Autoimmune SNN sera interact with more immune system proteins than healthy controls (ProtoArrays: 271/863 vs. 14/863, HuProt: 112/1694 vs. 39/1694, both p<0.0001). Overrepresentation was observed in all immune sub-pathways, including innate, adaptive immune responses, and cytokine signaling. Anti-FGFR3-positive SNN patients were more reactive with immune system proteins than negative ones. The independent SNN cohort validated the finding of overrepresentatively targeted immune system pathways. Validation with dot blot and ELISA confirmed reactivity to TRIM21 and IL-6, and identified anti-IFN-γ-positive SNN patients. IFN-γ levels correlated weakly with levels of anti-IFN-γ antibodies (Pearson’s r = 0.22, p=0.03). We conclude that the antibody repertoire of autoimmune SNN targets pathways of the innate and adaptative immune system, potentially reflecting key disease-related immune pathways and highlighting the systemic role of immune dysregulation in SNN.

Investigation of Immunoreactivity Profiles and Epitope Landscape in Divergent COVID-19 Trajectories and SARS-CoV-2 Variants

Bihani, Surbhi; Ray, Arka; Borishetty, Dhanush; Tuckley, Chaitanya; Salkar, Akanksha; Acharjee, Arup; Shrivastav, Prithviraj; Shrivastav, Om; Shastri, Jayanthi; Agrawal, Sachee; Duttagupta, Siddhartha; Srivastava, Sanjeeva
J. Proteome Res..
Jan 2025
This study aimed to elucidate the complexity of the humoral immune response in COVID-19 patients with varying disease trajectories using a SARS-CoV-2 whole proteome peptide microarray chip. The microarray, containing 5347 peptides spanning the entire SARS-CoV-2 proteome and key variants of concern, was used to analyze IgG responses in 10 severe-to-recovered, 9 nonsevere-to-severe cases, and 10 control case (5 pre-pandemic and 5 SARS-CoV-2-negative) plasma samples. We identified 1151 IgG-reactive peptides corresponding to 647 epitopes, with 207 peptides being cross-reactive across 124 epitopes. Nonstructural protein 3 (nsp3) exhibited the highest number of total and unique epitopes, followed by the spike protein. nsp12 had the most number of cross-reactive epitopes. Peptides from the spike protein and nsps 2, 3, 5, and 13 were notably associated with recovery. Additionally, specific mutations in SARS-CoV-2 variants were found to alter peptide immunoreactivity, with some mutations (e.g., G142D, L452R, and N501Y) enhancing and others (e.g., R190S and E484 K) reducing immune recognition. These findings have critical implications for the development of diagnostics, vaccines, and therapeutics. Understanding the distribution of epitopes and the impact of viral mutations on antigenicity provides insights into immune evasion mechanisms, informing strategies for controlling COVID-19 and future coronavirus outbreaks.

High-throughput identification of immunoreactive peptides and corresponding proteins from Anaplasma platys and Ehrlichia canis using peptide microarray chips

Llanes, Alejandro; Madesh, Swetha; Brangulis, Kalvis; Rajeev, Sreekumari
Front Cell Infect Microbiol.
Jan 2025
10.3389/fcimb.2025.1671309
INTRODUCTION: Anaplasma platys and Ehrlichia canis are rickettsial pathogens infecting dogs, with a worldwide distribution. Both species are obligate intracellular pathogens and colonize bone marrow-derived cells, with coinfections frequently reported in dogs. Although E. canis immunodominant proteins have been thoroughly characterized, very few high-throughput studies have been conducted to identify immunogenic proteins from Anaplasma spp. In this study, we used a methodology based on peptide microarray chips to identify immunoreactive peptides, either shared or species-specific, in the complete theoretical proteomes of both pathogens. METHODS: B-cell epitopes were predicted in the corresponding proteins from both species and ranked for synthesis on the peptide microarrays. These microarrays were screened with serum samples from antibody-positive dogs, as well as negative control sera from unexposed dogs. Additionally, we assessed the feasibility of integrating evidence gathered at the level of individual peptides to identify potentially immunogenic proteins contributing to the patterns of immunoreactivity observed on microarrays. RESULTS: Screening of peptide microarrays resulted in complex antibody reactivity patterns against thousands of peptides. After discarding peptides with cross-reactivity to negative control sera, we identified over 1,200 immunoreactive peptides, including ~80 peptides shared between the two species with almost identical sequences. Despite screening linear peptides, we were able to identify proteins previously reported as immunodominant in E. canis, some of which contain predominantly conformational epitopes. DISCUSSION: Our results suggest that a high-throughput strategy based on peptide microarrays is an effective approach for the rapid identification of immunoreactive peptides and the underlying immunogenic proteins. This study provides a foundation for developing novel diagnostic tools and vaccine candidates against A. platys and E. canis, including potential combined or multivalent formulations targeting both pathogens.

Functional screening for anti-CMV biologics identifies a broadly neutralizing epitope of an essential envelope protein

Gardner, Thomas J.; Stein, Kathryn R.; Duty, J. Andrew; Schwarz, Toni M.; Noriega, Vanessa M.; Kraus, Thomas; Moran, Thomas M.; Tortorella, Domenico
Nat Commun.
Dec 2016
The prototypic β-herpesvirus human cytomegalovirus (CMV) establishes life-long persistence within its human host. The CMV envelope consists of various protein complexes that enable wide viral tropism. More specifically, the glycoprotein complex gH/gL/gO (gH-trimer) is required for infection of all cell types, while the gH/gL/UL128/130/131a (gH-pentamer) complex imparts specificity in infecting epithelial, endothelial and myeloid cells. Here we utilize state-of-the-art robotics and a high-throughput neutralization assay to screen and identify monoclonal antibodies (mAbs) targeting the gH glycoproteins that display broad-spectrum properties to inhibit virus infection and dissemination. Subsequent biochemical characterization reveals that the mAbs bind to gH-trimer and gH-pentamer complexes and identify the antibodies’ epitope as an ‘antigenic hot spot’ critical for virus entry. The mAbs inhibit CMV infection at a post-attachment step by interacting with a highly conserved central alpha helix-rich domain. The platform described here provides the framework for development of effective CMV biologics and vaccine design strategies.

Identification of novel antigens contributing to autoimmunity in cardiovascular diseases

Müller, Anna-Maria; Bockstahler, Mariella; Hristov, Georgi; Weiß, Christel; Fischer, Andrea; Korkmaz-Icöz, Sevil; Giannitsis, Evangelos; Poller, Wolfgang; Schultheiss, Heinz-Peter; Katus, Hugo A.; Kaya, Ziya
Clinical Immunology.
Dec 2016
In myocarditis and dilated cardiomyopathy (DCM) patients the immune system may play an important role in disease progression. In this study, we aimed to identify new antigens as a target for autoimmune response that might play a crucial role in these diseases. Therefore, a peptide-array was used to investigate antibody binding profiles in patients with autoimmune myocarditis or DCM compared to healthy controls and thus to identify disease relevant antigens. To analyze the pathogenicity of the identified antigens, an experimental autoimmune myocarditis (EAM) model was used. Hereby, 3 peptide sequences, derived from myosin-binding-protein-C (MYBPC) fast-type, RNA-binding-protein 20 (RBM20), and dystrophin, showed pathogenic effects on the myocardium of mice. In summary, 3 potentially cardiopathogenic peptides (MYBPC fast-type, RBM20, dystrophin) were identified. Thus, this study could serve as a basis for future investigations aimed at determining further antigens leading to pathogenic effects on the myocardium of DCM as well as myocarditis patients.

Antibody Binding Studies Reveal Conformational Flexibility of the Bacillus cereus Non-Hemolytic Enterotoxin (Nhe) A-Component

Didier, A.; Dietrich, R.; Märtlbauer, E.
PLoS ONE.
Oct 2016
The non-hemolytic enterotoxin complex (Nhe) is supposed to be the main virulence factor of B. cereus causing a diarrheal outcome of food poisoning. This tripartite toxin consists of the single components NheA, -B and -C all of them being necessary for maximum toxicity. In the past, research activities aiming to elucidate the mode-of-action of Nhe were mostly focused on the B- and C-component. In this study the generation of novel monoclonal antibodies (mAb) and their thorough characterization enabled the determination of key features for NheA. By the means of immunoaffinity chromatography it could be shown that NheA does not interact with -B and -C in solution. Additionally, the establishment of a highly sensitive sandwich-EIA now enables the detection of NheA in B. cereus supernatants down to 20 pg ml-1.Peptide-based epitope mapping in combination with partially deleted recombinant NheA fragments allowed the allocation of the binding regions for the three mAbs under study. Furthermore, by different EIA set-ups the conformational flexibility of NheA could be shown. For two of the antibodies under study different mechanisms of NheA neutralization were proven. Due to prevention of complete pore formation by one of the antibodies, NheA could be detected in an intermediate stage of the tripartite complex on the cell surface. Taken together, the results obtained in the present study allow a refinement of the mode-of-action for the Nhe toxin-complex.

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